Sen. Mark Kirk claimed President Barack Obama was “acting like the drug dealer in chief” for making a $400 million cash payment to Iran that was tied to the release of American prisoners.

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In this June 9, 2014, file photo, U.S. Sen. Mark Kirk, R-Ill., speaks in his office in Chicago. Kirk said President Barack Obama was “acting like the drug dealer in chief” when his administration delivered $400 million in cash to Iran contingent on the release of American prisoners. Kirk made the remarks during an editorial board meeting with The (Springfield) State Journal-Register in mid-August 2016.

Sen. Mark Kirk claimed President Barack Obama was “acting like the drug dealer in chief” for making a $400 million cash payment to Iran that was tied to the release of American prisoners.

During an interview with the State Journal-Register editorial board last week, Kirk claimed Obama gave “clean packs of money” to a “state sponsor of terror” and warned that “those 500-euro notes will pop up across the Middle East.”

Last week, the Obama administration claimed the $400 million payment was used as leverage to push for the release of four U.S. prisoners, NBC News reported.

The payment was announced in January, a day after the four Americans were freed and on the same weekend U.N sanctions against Iran were lifted. The White House and State Department have denied Republicans’ claims that the transaction served as a ransom payment, claiming that the timing was coincidental.

Secretary of State John Kerry released a press release at the time, noting that the $400 million was used by Iran to purchase military weapons and equipment from the U.S. while the shah was still in control, prior to the 1979 Iranian Revolution.

“Iran will receive the balance of $400 million in the Trust Fund, as well as a roughly $1.3 billion compromise on the interest,” Kerry said in a statement in January.

On Monday, the Kirk campaign continued to call the payment into question.

“After using unmarked cargo planes to deliver pallets of foreign currency totaling over $400 million to Iran to get our hostages back, the (Obama) Administration is now attempting to change the literal definition of ‘ransom,’” Kirk spokesman Kevin Artl said in a statement. “Sen. Kirk believes the administration’s actions, which Tammy has supported, were reckless in the extreme. The administration’s pay off will endanger more Americans abroad (and) is almost certain to fund terrorism."

According to his campaign, the senator will hold an oversight hearing on the payment next month as part of his role as chairman of the Senate Subcommittee on National Security and International Trade and Finance.

Earlier this month, Kirk issued a release about the “ransom payment.” The senator said Congressional hearings were “the only way for the American people to fully know whether their tax dollars went directly to Iran’s terrorist Islamic Revolutionary Guard Corps.”

“What (Kirk) said about President Obama was totally inappropriate and he must apologize,” Kelley said in a statement. “It’s another example of Kirk’s long history of insulting the president which is now matching up with the hateful and ‘birther’ space carved out in the public sphere by fellow Republican Donald Trump to dehumanize Barack Obama.”